1. Field of the Invention
The present invention relates to a refueling nozzle which is suitable for use at an oil station, easily inserted and engaged in a fitting manner to a filler opening of a fuel tank and capable of avoiding any erroneous operation.
2. Description of the Related Arts
Discharge of fuel vapor must be prevented as much as possible at the time of refueling to a vehicle or vessel from the point of view of environmental protection and also to ensure the health of oil station personnel. Considering the current situation, and, moreover, a self-refueling system wherein customers are requested to make the refueling, discharge of fuel vapor has to be prevented more intensively and various proposals have been made for this purpose.
One of the means for avoiding discharge of fuel vapor is to seal up a gap which exists between a refueling nozzle and a filler opening. The Japanese Patent Laid-Open Publication No. 4697/93 discloses a method of sealing up a gap which exists between a head portion of a refueling nozzle and a filler opening by arranging, at the external circumference of the head portion of the refueling nozzle, a rubber berrow tube which can be filled with air and, after inserting the refueling nozzle into the fuel tank, filling up the berrow tube with air thereby inflating the portion of the berrow tube inserted into the fuel tank by filling the berrow tube with air. However, this method has the disadvantage that the structures of a refueling apparatus and a refueling nozzle have to be complicated because a mechanism is required to fill the rubber berrow tube with air and to exhausting the air therefrom.
The Japanese Patent Laid-Open Publication No. 97198/93 discloses an oil-proof rubber vapor collector which easily seals a filler opening by forming a head portion into a bell-flare shape. However, such a vapor collector cannot seal a filler opening of a fuel tank tightly.
Another function that a refueling nozzle is requested to have is that it is engaged fixed to a filler opening of a fuel tank. For example, the above Japanese Patent Laid-Open Publication No. 4697/93 discloses that the refueling nozzle can be engaged with the filler opening by inflating the part of the berrow tube inserted into the fuel tank. However, as explained above, this method has the problem that a mechanism for filling the rubber berrow tube with air and exhausting the air therefrom is required, thereby complicating the structures of the refueling apparatus and the refueling nozzle.